Detachable terminal fitting for stranded-wire structure



Dec. 24, 1946. A. E. BRICKMAN 2,412,948

DETACHABLE TERMINAL FITTING FOR STRANDEDWIRE STRUCTURE Filed Feb. 2,1943 2 Sheets-Sheet 1 Dec. 24, 1946. A. E. BRICKMAN 2,412,948

DETACHABLE TERMINAL FITTING FOR STRANDED-WIRE STRUCTURE Filed Feb. 2,1943 2 Sheets-Sheet 2 FIE- FIE-9 rim a INVENTOR.

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- Patented Dec. 24, 1946 UNITED STATES PATENT orrics DETACHABLE TERDHNALFITTING FOR STRANDED-WIRE STRUCTURE Alan E. Brickman, New Haven, Conn.,assignor to The American Steel and Wire Company of New Jersey, acorporation of New Jersey Application Fejruary 2, 1943, Serial No.474,416

I 6 Claims. (Cl. 24-12215) This invention relates to a detachableterminal fitting, and inparticular to such fittings used on strandedwire structures. At present all terminals are fixed to the end of thestranded wire structure so as to become a unitary part of the assembly.If the terminal becomes worn or damaged, the whole assembly must bereplaced. All aperturesthrough which the cable passes must be equal toor greater thanthe largest cross-section of the attached terminal. Theselarge apertures weaken the structure and/or permit undesir a b1einfiltration of moisture, gases or foreign materials and are especiallydetrimental when used on aeroplanes. In the present fixed terminalsthere is no im- Imediate provision for changing the overall length oithe cable assembly. Such change is often necessary due to lengtheningresulting from structural stretch of the cable or from wear, which isparticularly noticeable in cable connections involving marked changes incourse of direction, as accomplished with sheaves. The present usedcable connector with fixed terminals must, theretore, include aturnbuckle or a stud fitting with nut vtakeup on at least one end tocompensate for the changes in cable assembly length.

It is an object of this invention to furnish a detachable terminalfitting which permits greater flexibility oi. terminal design.

Another Object is to furnish a terminal fitting which may be readilyremoved or replaced.

A iurther object is to furnish a terminal fitting having provisions forchanging the overall length of the cable assembly.

These and other objects will be more apparent alter referring to theattached drawings in which: Fig. 1 is a view or a stranded wirestructure used in the invention; 1

Fig. 2 is a view or such a wire structure after its end has beenbroomed;

Fig. 3 is a view, partly in cross-section, showing a fitting attached tothe stranded wire structhe terminal fitting of the Fig. shows thefitting of Fig. 8 swaged on the wire rope;

Fig. 11 is a view similar to Fig. 10, but showing the fitting with thethreads formed thereon, and Fig. 12 is a view showing an assembly of thesecond embodiment of the invention.

Referring more particularly to the drawings, reference numeral 2indicates a stranded wire structure'to which a fitting'is to beattached. The wire structure is broomed toobtain a bulb 4 a shortdistance from the end thereof and an enlarged broomed section 6 at theend thereof as shown in Fig. 2. The end or the wire structure is theninserted into the cavity of a die and molten metal is injected into the"cavity of the A detachable terminal fitting it having a bore it formedtherein is produced by the injection method of die casting. A Dardeletthread i8 is cast therein and a thread tap is run over the cast threadto clean and finish the working surfaces. A set screw 20 is then screwedinto the bottom of the bore l6. By adjusting this screw the bottomingpoint may be changed as desired.

The operation of the Dardelet thread. will be apparent from aninspection of Figs. 6- and '7. The root portion 22 of the male threadisv tapered so asto cause an incline in the direction of the end andthere is a corresponding taper 24 on the crest portion of the femalethread. The two members may be readily screwed together until they meetwith resistance, which in this instance takes place when the fitting 8abuts the plug 20. With the additional torque, the crest taper producesa great compressive force on the root taper oi! the cable member, which,in turn, will transmit the compression-tomes onto the stranded wirestructure to increase the grip on the stranded structure to betterwithstand the tension which will be applied to the assembly. Fig. 7shows the position of the thread when additional torque is applied. Toprovide changes in the overall assembly length, the plug 20 may beadjusted inwardly or outwardly by means of a set screw wrench 26. Asecond embodiment of the invention is disclosed in Figs. 8 to 12. Inthis embodiment a tubular nickel steel seamless ferrule 21 provided witha bore 28 having a diameter comparative to the outside diameter of thewire structure is slid over the wire. The ferrule is then swaged overthe greater part of its length'so as to cause fiow of metal into theexternal inter.-

5d stlces and in fist grip with the stranded wire structure as shown inFig. 10. The finished wall section on the ferrule in this constructionmay be extremely thin, as it becomes augmented with the values producedby the detachable terminal H as described. above. The unswaged' length29' structure. This method of evading a line of restraint to cablevibration is not as effective as the method disclosed above. After theferrule 21- is swa'ged onto the wire, a Dardelet thread 30:

tures comprisinga thinwalled compressible fitting surrounding and inintimate surface contact with said stranded wire structure and having; aDardelet thread formed on the external surface thereof, and a hollowfitting having a complemental Dardelet thread formed on the internalsurface thereof and threaded on said firstnamed fitting, saidcomplemental threads being tightened to compress the compressiblefitting whereby the gripping force on the wire structures is increased.

2. A terminal fitting for stranded wire structures comprising a thinwalled compressible fitting surrounding and in intimate surface contactwith said stranded wire structure and having a Dardelet thread formed onthe external surface thereof, and a hollow fitting having a complementalDardelet thread formed on the internal surface thereof and threaded onsaidfirst-named fitting, said complemental threads being tightened tocompress the compressible fitting wherebythe gripping force on the wirestructures is increased, said hollow fitting having an adjustable bottomtherein to provide changes in the assembled length of the terminalfitting.

3. A terminal fitting for stranded wirestructures comprising a thinwalled compressible male fitting cast about said stranded wirestructure,

and having a Dardelet thread formed on the externalsurface thereof, anda hollow fitting having a complemental Dardelet thread formed. on

the internal surface thereof and threadedon said first-named fitting;said complemental threads being tightened to compressthe compressiblefitting whereby the gripping force on the'wire structures is increased.

4. A terminal fitting for strandedwlre struc-- tures comprising a thinwalled compressible male fitting'ca'st about ,said stranded wirestructure, and having a Dardelet thread formedon the ex-' ternal surfacethereof, and a hollow fitting having a complemental Dardelet threadformed on" tures is increased, said hollow fitting having an adjustablebottom therein to provide changes in the'a'ssembled length of theterminal fittingi 5. A- terminal fitting for stranded wire 'struc--turescomprising a thin walled compressible irial'e fitting swaged to andsurrounding the wire structureand having a Dardelet thread formed-on moexternal surface thereof, and a hollow fitting having a complementalDardelet thread formed on the internal surface thereof andthreaded onsaid first-named fitting, said complemental threads being tightened tocompress the compressibl ej'fitting whereby the gripping force on thewire" struc-' tures is increased.

6. A terminal fitting for strandedwire structures comprising a thinwalled compressible'male fitting swaged to and surrounding the wirestructure and having a Dardelet thread formed on the external surfacethereof, and a hollow fitting having a complemental Dardelet threadformed on the internal surface thereof, and threaded on said first-namedfitting, said complemental threads being tightened to compress thecompressible fitting whereby the gripping force on the wire structuresis increased, said hollow fitting having an adjustable bottom thereinto, provide changes in the assembled length of the terminal fitting,

ALAN E. BRICKMAN.

